This engine has the dubious credit of giving diesel engines a bad name in the domestic market since their inception. I've heard that poor reliability was the culprit. I've also heard that GM made them better before the end (too late) and that there are things that can be done to make these good engines.

I like the fact that they are based on a BOP engine and will fit into almost ANY Rear Drive GM product you could think of. I presume they are of lighter weight than a 6.2/6.5.

The downside I see is finding BOP transmissions suitable for a Diesel...but you'd normally find them as a pair I guess.

The 4.6 also falls into this topic. Were they FWD only, or did they come RWD as well...or can the same engine be used in either configuration?

My biggest question, is: What does it take to make one of these engines reliable?

I do agree with you in that this engine has been given a bad rap and as such effected the reputation of automotive diesels in general. For a large part the reputation was well deserved as the earlier versions were notorious.

On the plus side, the General did rise to the occasion and the ones subsequent to 1981 (DX block) had most of the bugs worked out. After 81 the only real problems were head related. Interestingly enough, the 6.2 suffered from some of the same problems ergo cracking between the valves, head bolt stretching, head gaskets, etc.

The pumps (now manufactured by Stanadyne)continued to have upgrades to the internals as the original was designed for a tractor engine and the extended use in an automotive engine resulted in some wear and function problems.

In answer to your questions the only difference in the trannys was in the torgue converter and the govenor, both easily rectified problems though it will be much easier to find the Chevy based bellhousings then the BOC patterns. As far as fit is concerned, the 5.7 is only about 150 lbs lighter then the 6.2, but the 6.2 has a much wider application base then the 5.7 as it is based upon the standard Chev small block configuration.

Can it be made to be reliable? In a word "yes". The big question is do you want to. I spent almost 20 years doing what you propose but try as I might, either you built it to be reliable or you built it to produce power. The two seem to be mutually exclusive.

In my final attempt I installed a 5.7 with all the reliablility mods into a 1986 Cadillac (straight bolt in conversion) Fleetwood. Alone the engine was capable of moderate acceptability from a drivability point of view and gave incredible fuel mileage (40 plus MPG (Imp)) but it had absolutely no power. Would cruise all day at 70 MPH giving great mileage but as soon as you got into the hills it didn't have enough power to blow itself to hell. Passing? not a chance. Got four miles and a good stiff tail wind?

Making them reliable consisted of making sure you had a good set of crack free heads (hard to find) the last variant of head bolts properly torqued and double coolant lines from the back of the heads. The pump had to be set up right and the timing mechanism working properly and set up for no more then 120 HP. Other then that the bottom ends were bullet proof after 81 and the timing chain should be replaced every 70K just on spec. (better safe then sorry). Change oil every 3k, good fuel and you'll be all right.

The 6.2 makes for a much better conversion, though there are stilll some issues with fit, but the result is a much more tractable engine and much better parts availablility.

Hope this helps

Bill

91 Buick Roadmaster wagon, GM 6.2 diesel conversion (gone but not forgotten89 GMC 6.2 (Just got rid of the last pieces)84 Mercedes 300D (gone to the great autobahn in the sky)94 Cadillac Fleetwood (Sold before I could convert it)

I wasn't aware that they were so gutless. I was figuring they would underpowered...but not by that much. I guess that tells me what I need to know about the 5.7 and that, unless I stumble across one some day...I don't need to go seeking them out.

The smaller engine you reference is the 4.3L. It came in a couple forms as a V6 and there was also a 4.3 V8 in '79 and '80.

The 4.3 V8 was used only in the A/G body cars (rear drive Cutlass and the like). The 4.3 V6 was used in those same cars begining in 1982 with cast iron heads. In the front drive A bodies (Celebrity/Pontica6000/Olds Cutlass Ciera/Buick Century the V6 used aluminum heads and the water outlet was to the rear of the engine (meaning a diferent intake manifold). The V6 was the most upgraded of the Olds diesels, but by the time it came out, gasoline supply and price had stabilized from the 1979 shortages and the early Olds diesels had aquired a rather bad reputation, thus the market pretty much dried up for the American diesel cars.

All the V6 variants are very rare today as are the 4.3 V8's. Any 4.3 V8 that had a warantee problem was replaced with a 5.7. I have a 4.3 V6 Cutlass Cierra and 2 of the 4.3 V8 cars, one still has it's original engine. The other was replaced with a DX 5.7 sometime during it's early life.

Parts and cars still turn up, usually cheap. I've been collecting stuff for about 8 years now and have enough parts to last a lifetime, including a couple brand new engines.

BTW, as an experiment on one of my 5.7 cars, I reused a cracked pair of cylinder heads with no ill effects. They commonly crack between the intake and exhaust valves.

Overall, I consider them worthy, although it helps greatly if you can work on them yourself. To have to pay someone would make it to expensive to be worthwhile. (even if you can find someone knowlegable to do the work)

I have a 1981 Chev Caprice Classic, looks real nice and drives out well. Diesel engine runs great once you get it started! I drive it a couple times a week, but after 70K miles and all the expenses on keeping the engine running, I'm just proud as I can be that I can still get in it and hear that diesel engine clatter. It is cool to pull into a fuel station and have everyone look around and finally figure out it is the ole Caprice with a diesel that they hear.

That being said, there will be some modifications to make it work. Try to aquire a complete engine, with all accessories included. This will give you the brackets you need to mount the power steering, alternator and A/C compressor. Make sure the engine has all it's pulleys too. They are a bit different from the Chevy to the Olds.

Olds and Chevy used a few different types of motor mounts too. You'll need the Olds engine mount and either the Olds or Chevy frame brackets. There were a few different variations over the years, but some time spent in a junkyard looking at various Olds powered and Chevy powered stuff should yield parts to do the job. Olds gas and diesel engines shared mounts, brackets and mounting and will completely interchange, so parts from a Olds gas powered vehicle will work.

Transmission bellhousing patterns are different between the two. A 77 Chevy van with an auto would have used the turbo hydramatic (TH)350 transmission. Some of them have both the Chevy pattern and the (Buick/Olds/Pontiac/Cadillac) patterns. There are also many of the BOPC versions still out there. An adapter can also be used and are available in the aftermarket for less than $100.

The easiest way to put a diesel in your van from an availability and interchangeability standpoint is to use the 6.2/6.5 Chevy/GM diesel. It is completely interchangeable with the V8 Chevy gas engine and if your van has a 6 cylinder, only the mounts may have to be changed. Those engines are far more common, more powerful and more reliable. If you buy one of those, try to get it complete as well.

ok guys, i need to run this by you. first time ive ever owned a diesel. its in the cadillac my name suggests, so from what ive read of this post, ive got a somewhat...less desireable diesel.

heres what happened. gas gauge not working, i rode out into a cold december morning. she started surging, and bieng very erratic before it gave up the ghost and died.

i put more diesel in it, along with a fair amount of fuel conditioner. it started, but the surging persisted. i got it to my work, and by then it had mellowed out. i hear from the mechanics at my work ( i work in a body shop) that i've moe than likely got a bubble in the air line, that would need to be bled before anything else happened.

bad news, i didnt do this. i started it up 5 hours later, and it was running smoothly, so i thought it had cleared up. by the time i get home, a 15 minute drive, it starts again! what the hell? i put 20$ worth of diesel, and a good chunk of fuel conditioner in it.

Hi, Cadi 80,It sounds as if your fuel filter has plugged up. This can cause the surging. It may be that the old rubber hoses are leaking air into the system if the fuel pump is sucking hard on the lines. Look for smoke too. That filter is more expensive then say a detroit diesel filter or even a 6.9 IH filter. So if you start experimenting with different fuels, you might consider going to a cheaper filter and housing.DF

"I don't work with collectives. I don't consult, I don't co-operate, I don't collaborate."Howard Roark

Hi there, I have a 72 Olds 2dr with a DX350 , would you happen to have a good fuel pump you could sell us, (stanadyne,roosa) cheers, fishboy.milesfish@vodafone.net.nz

quote:

Originally posted by turbobill:I have a small collection of the Olds diesels, parts and cars.

The smaller engine you reference is the 4.3L. It came in a couple forms as a V6 and there was also a 4.3 V8 in '79 and '80.

The 4.3 V8 was used only in the A/G body cars (rear drive Cutlass and the like). The 4.3 V6 was used in those same cars begining in 1982 with cast iron heads. In the front drive A bodies (Celebrity/Pontica6000/Olds Cutlass Ciera/Buick Century the V6 used aluminum heads and the water outlet was to the rear of the engine (meaning a diferent intake manifold). The V6 was the most upgraded of the Olds diesels, but by the time it came out, gasoline supply and price had stabilized from the 1979 shortages and the early Olds diesels had aquired a rather bad reputation, thus the market pretty much dried up for the American diesel cars.

All the V6 variants are very rare today as are the 4.3 V8's. Any 4.3 V8 that had a warantee problem was replaced with a 5.7. I have a 4.3 V6 Cutlass Cierra and 2 of the 4.3 V8 cars, one still has it's original engine. The other was replaced with a DX 5.7 sometime during it's early life.

Parts and cars still turn up, usually cheap. I've been collecting stuff for about 8 years now and have enough parts to last a lifetime, including a couple brand new engines.

BTW, as an experiment on one of my 5.7 cars, I reused a cracked pair of cylinder heads with no ill effects. They commonly crack between the intake and exhaust valves.

Overall, I consider them worthy, although it helps greatly if you can work on them yourself. To have to pay someone would make it to expensive to be worthwhile. (even if you can find someone knowlegable to do the work)

So I'd like to drop a Diesel engine in an s10 Blazer. I was hoping to do a 6.5l turbo diesel except that is way huge and would require a lot of modification/custom work. So I thought what about using a 350 v8 with the DX block? I'm mostly after high fuel economy and a budget diesel conversion.

My thought was using a diesel 350 v8 block I could use a lot of the parts out there already made for doing v8 conversions. But if Olds and Chevy use different engine mounts, would that mean I couldn't use the standard v8 conversion engine mounts?

Originally posted by fishboy:Hi there, I have a 72 Olds 2dr with a DX350 , would you happen to have a good fuel pump you could sell us, (stanadyne,roosa) cheers, fishboy.milesfish@vodafone.net.nz

quote:

Originally posted by turbobill:I have a small collection of the Olds diesels, parts and cars.

The smaller engine you reference is the 4.3L. It came in a couple forms as a V6 and there was also a 4.3 V8 in '79 and '80.

The 4.3 V8 was used only in the A/G body cars (rear drive Cutlass and the like). The 4.3 V6 was used in those same cars begining in 1982 with cast iron heads. In the front drive A bodies (Celebrity/Pontica6000/Olds Cutlass Ciera/Buick Century the V6 used aluminum heads and the water outlet was to the rear of the engine (meaning a diferent intake manifold). The V6 was the most upgraded of the Olds diesels, but by the time it came out, gasoline supply and price had stabilized from the 1979 shortages and the early Olds diesels had aquired a rather bad reputation, thus the market pretty much dried up for the American diesel cars.

All the V6 variants are very rare today as are the 4.3 V8's. Any 4.3 V8 that had a warantee problem was replaced with a 5.7. I have a 4.3 V6 Cutlass Cierra and 2 of the 4.3 V8 cars, one still has it's original engine. The other was replaced with a DX 5.7 sometime during it's early life.

Parts and cars still turn up, usually cheap. I've been collecting stuff for about 8 years now and have enough parts to last a lifetime, including a couple brand new engines.

BTW, as an experiment on one of my 5.7 cars, I reused a cracked pair of cylinder heads with no ill effects. They commonly crack between the intake and exhaust valves.

Overall, I consider them worthy, although it helps greatly if you can work on them yourself. To have to pay someone would make it to expensive to be worthwhile. (even if you can find someone knowlegable to do the work)

About a year ago, I sold a bunch of spare reman injection pumps on ebay. The ones remaining are for my current vehicles.

Originally posted by 6.5l TD SVO:So I'd like to drop a Diesel engine in an s10 Blazer. I was hoping to do a 6.5l turbo diesel except that is way huge and would require a lot of modification/custom work. So I thought what about using a 350 v8 with the DX block? I'm mostly after high fuel economy and a budget diesel conversion.

My thought was using a diesel 350 v8 block I could use a lot of the parts out there already made for doing v8 conversions. But if Olds and Chevy use different engine mounts, would that mean I couldn't use the standard v8 conversion engine mounts?

Some of the frame bracket/motor mount combo's on the GM stuff are nearly interchangable between Olds and Chevy, others aren't.

The best way to do your conversion is get the motor mounts/frame brackets from an Olds powered car. many of the 80's full size body/frame big GM B and C cars were Olds powered, as were some of the intermediate A/G bodied full frame cars.

I have just acquired 1981 caprice classic Diesel its my first diesel and don't know much about diesel engines. Here is the scoop Car was parked for 12 yearshad very less mileage, I sprayed some starter fluid....jumped started with old batteries in.... put some oil rated diesel about 2 quarts put some water and drove 50 mile till I saw the light for over heat. after some time put about gallon of antifreeze put some more oil and couple new batteries then sprayed the carb and it ran another 50 mile till I got to home....it was dripping oil badly when in parked position.....after getting home I replaced the water pump, all belts, thermostat, coolant, radiator, hoses,glow plugs, glow plug switch, (controller on the way), blower motor and fixed the relay. I have also replace other relays ac and one more mounted on the fire wall...oh also changed oil and filter.

here is the question **what else I need to do to make sure it won't die on me while on a trip?**what is causing the oil leak ...it is coming from the driver side on top of starer??**do I need to change oil pan gasket, head gasket oil-pump gasket etc....and how hard these jobs are I have no means to lift the engine except a floor Jack and couple of metal supporter??** When the car is running it seems to throw the coolant out, before even it gets hot..and started to fill the reservoir...why???** Radiator has four sets of line going in to it Two big from the front and two small from the back...does it matter if the small line are attached to any hole since the size is the same, if yes How should they be attache??

Sorry CCD. You've got at least one maybe two heads that are cracked (common 5.7 problem). At the very least the head gasket is toast. The problem with just changing the head gasket, is that over the years, I have seen tons of these heads and only about 10% of them WERE NOT CRACKED. Your experience with the coolent is a classic symptom.

It is possible that your liberal application of starting fluid may have been the culprit. never, never use ether in a pre-chamber diesel !!!. By the way, diesels don't have carbs.

From the sounds of it, I would pull the engine and give it a thorough freshening up, new heads (Clearwater Heads still sell them I believe), solid copper head gaskets and ARP studs. Look down close to the motor mounts and check for a "DX" cast into the block. If you don't have a DX block, don't invest any money in this engine. It will only make you cry. The DX was the last varient of this engine and it was reasonably reliable and gave incredible fuel mileage. Given the age, it is more then likely that this is the second (or even third) engine in this car (GM just kept replacing them under warrantee), meaning you probably do have the DX block.

Your oil leak is probably from the valve cover gasket. Older sytle cork and rubber. Probably dried out over the years. Same story for the rest of the gaskets.

Sorry for the bad news. Let us know how you make out.

Bill

91 Buick Roadmaster wagon, GM 6.2 diesel conversion (gone but not forgotten89 GMC 6.2 (Just got rid of the last pieces)84 Mercedes 300D (gone to the great autobahn in the sky)94 Cadillac Fleetwood (Sold before I could convert it)

Thanks McD..hear is the scoop I ended up hiring a backyard Mechanic to do the gaskets Job. We just got done oil leak is most probably form the oil pan gasket and my Mechanic did not want to do that.....Oh well. after we put together every thing and started the car it took long time to get this thing fire up ...........once it started running it develop a noise that is almost like a backfiring but not sure it definitely was coming from the top of throttle body (sounded like the exhaust pipe was taken out from motorcycle) My Mechanic did not know what might have caused this noise and I am sure it was not there before!!!! Need some help could you tell me what it is...one of the guess he is making it could be exhaust regulator (top of throttle/ Under the air cleaner) went bad!! is is possible....or could it be throttle positioning sensor!!! or what else could be need some serious help.

Thanks in advance for all your help

oh one more thing how hard of job it is to do the oil pan gasket replace since he won't do?? is is some thing one should do himself or how much would it cost to get this done?? any idea??

First of all, get another mechanic that knows diesels. The valve under the air cleaner is the EGR valve and yes this might be stuck open. Better to just remove it and plug the port. Even better to remove the intake and plug both sides of the exhaust ports so you don't have a hot pipe heating up your intake air.

These engines have very tight tolerences for the valve guides. As they age, sometimes a valve will hang up, especially if the engine has not been started for a few days. This can be as simple as a puffing noise (caused by the valve cracked open) to a strong mechanical knock (valve is being slammed shut by the piston). This usually disappears after the engine warms up but has been known to punch a hole in the effected piston.

You really shouldn't worry about the oil leaks as much as your head gasket/cracked head problem. This is going to let you down and very quickly. This problem has to be addressed.

As far as doing the pan gasket in situ, you can do it but plan on at least a good weekend to get er done. You will have to jack the engine up off its mounts to give you enough clearance to remove the pan without damaging the oil pick-up. You may find when you get the pan off that it was the real crankshaft seal. This also can be replaced in the car but not the kind of job I would undertake. In my opinion, for the time needed to pull the engine, your better off getting the thing out on a bench and do it all in one shot, including the heads.

Bill

91 Buick Roadmaster wagon, GM 6.2 diesel conversion (gone but not forgotten89 GMC 6.2 (Just got rid of the last pieces)84 Mercedes 300D (gone to the great autobahn in the sky)94 Cadillac Fleetwood (Sold before I could convert it)

Thanks again McD- would this problem be rectified with the replacement of new EGR valve. One thing I know (when I was ordering replacement parts they had asked me that) this engine came in two type of EGR valve one that is inside the Manifold and other is on the Outside. This is the one that is outside and very easy to replace ( at least it seems like)just want to confirm with you ...is that the first picture in the following link.

I need to ask another question does anyone out there know what other model of GM cam with the similar EGR valve. Mine (1981 caprice classic diesel)has the part number 17075598 but unable to locate it at rockauto parts or any where online. any and all the help is appreciated. Thanks in advance.

From what I remember the EGR was on the intake manifold just behind the air inlet on the passenger side.

quote:

Originally posted by Caprice_Classic_Diesel:I need to ask another question does anyone out there know what other model of GM cam with the similar EGR valve. Mine (1981 caprice classic diesel)has the part number 17075598 but unable to locate it at rockauto parts or any where online. any and all the help is appreciated. Thanks in advance.

~CcD~

Try Rockauto again. Just did and found many for this car (under emission). The 5.7 was used in all of the GM full size and a few mid sized cars from 81 to 85. It was also used in all of the 1/2 ton trucks from 1978 to 1982 (6.2 was introduced in 83).

91 Buick Roadmaster wagon, GM 6.2 diesel conversion (gone but not forgotten89 GMC 6.2 (Just got rid of the last pieces)84 Mercedes 300D (gone to the great autobahn in the sky)94 Cadillac Fleetwood (Sold before I could convert it)